A Power-Efficient High-Pass Delta-SigmaModulator for Neural Recording Systems

High-pass delta-sigma ADCs are relatively unexplored, but they offer certain advantages, such as immunity to 1/f noise and dc offset, that are highly desirable in sensor based applications. This paper investigates a switched-capacitor second order 4-bit high-pass delta-sigma modulator with 100 dB dynamic range as a promising power-efficient solution for neural recording systems. A power-aware design analysis supported with numerical expression and modeling performed in MATLAB/Simulink is presented. Analysis and simulation results obtained with VerilogA models show that dynamic biasing can reduce the power consumption by 33%.